Hi all. FYI, at Bangkok Immigration today, 4 April, they stayed open past normal hours to accommodate the large crowd. My husband went this morning for extension on his research visa, there were a lot of people, his ticket had a very high number. By 4:30pm, the normal closing time, there were still 100 people ahead of him. Long story short - they stayed open late. He got his visa done by 6:30pm, & they were still open. Can’t say if this will continue until Songkran, but just a heads up. And don't forget they're closed on Thursday, 6 April.
(My thought was that they wouldn’t just keep handing out tickets & make you sit there all day if they were unable to to complete them. Seems that was the case.)
TLDR : Answer Summary
A user shared their experience at Bangkok Immigration on April 4, noting that the office stayed open past regular hours due to high demand, allowing visa applications to be processed until 6:30pm. Comments from others indicate that while waiting times can be long, the immigration office typically accommodates everyone who gets a ticket before 3:30pm. Tips were offered, such as making appointments online to reduce wait times. Concerns were also raised about potential delays in other locations, like Trat Immigration, especially during peak periods such as Songkran.